At present, display technology of an electronic paper mainly includes black-and-white display, and the electronic paper includes electronic paper that employs electrophoretic display mode and electronic paper in electrowetting display mode, etc.
For an electronic paper that employs electrowetting display mode, the substrate of the electronic paper is consisted of a white substrate, a transparent electrode and a hydrophobic surface, and a black oil drop exists between hydrophilic columns. Generally, the transparent electrode is driven by an active structure, for example, it is driven by a Thin Film Transistor (TFT) array. When a voltage is applied to the substrate, the oil drop contracts on one side of the hydrophilic columns, and the ambient incident light irradiates onto the white substrate and is reflected, and then seen by human eyes as white light beams, as shown in FIG. 1. When no voltage is applied to the substrate, the oil drop tiled on the hydrophobic surface, and the incident light is absorbed by the tiled black oil drop layer, thereby the object of black display is attained, as shown in FIG. 2. When color display is to be performed, red, green and blue tricolor oil drops are feed into each unit respectively, as shown in FIG. 3. However, the problem of this solution is that the precision of ink jet feeding is limited, and accurate feeding cannot be realized for products with a high-resolution ratio. Or, as shown in FIG. 4, a color filter unit is added above the oil drop layer to realize color display. However, this solution will cause a large increase of the thickness of the product, which is a severe problem in product thinning and flexible display.
For an electronic paper that employs electrophoretic display mode, black or white electrophoretic particles are employed for this electrophoretic display mode, and the electrophoretic display particles are arranged orderly by changing an electric field applied, so that color development may be attained to present different pictures. As shown in FIG. 5, microcapsules containing black electrophoretic particles and white electrophoretic particles are formed between a lower white substrate formed with transparent electrodes and the upper transparent electrodes; wherein the black electrophoretic particles and the white electrophoretic particles contain different charges respectively, and when a voltage is applied to the substrate, the black electrophoretic particles and the white electrophoretic particles move to the upper and lower region of the microcapsules respectively, thus black-and-white display of the electronic paper can be realized. However, currently there is no color electronic paper that employs electrophoretic display mode.
In conclusion, the color display of an electronic paper cannot be well realized in the prior art.